util/cutils.c

   1 /*
   2  * Simple C functions to supplement the C library
   3  *
   4  * Copyright (c) 2006 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25 #include "qemu-common.h"
  26 #include "qemu/host-utils.h"
  27 #include <math.h>
  28
  29 #include "qemu/sockets.h"
  30 #include "qemu/iov.h"
  31 #include "net/net.h"
  32 #include "qemu/cutils.h"
  33
  34 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  35 {
  36     int len = qemu_strnlen(str, buf_size);
  37     memcpy(buf, str, len);
  38     memset(buf + len, pad, buf_size - len);
  39 }
  40
  41 void pstrcpy(char *buf, int buf_size, const char *str)
  42 {
  43     int c;
  44     char *q = buf;
  45
  46     if (buf_size <= 0)
  47         return;
  48
  49     for(;;) {
  50         c = *str++;
  51         if (c == 0 || q >= buf + buf_size - 1)
  52             break;
  53         *q++ = c;
  54     }
  55     *q = '\0';
  56 }
  57
  58 /* strcat and truncate. */
  59 char *pstrcat(char *buf, int buf_size, const char *s)
  60 {
  61     int len;
  62     len = strlen(buf);
  63     if (len < buf_size)
  64         pstrcpy(buf + len, buf_size - len, s);
  65     return buf;
  66 }
  67
  68 int strstart(const char *str, const char *val, const char **ptr)
  69 {
  70     const char *p, *q;
  71     p = str;
  72     q = val;
  73     while (*q != '\0') {
  74         if (*p != *q)
  75             return 0;
  76         p++;
  77         q++;
  78     }
  79     if (ptr)
  80         *ptr = p;
  81     return 1;
  82 }
  83
  84 int stristart(const char *str, const char *val, const char **ptr)
  85 {
  86     const char *p, *q;
  87     p = str;
  88     q = val;
  89     while (*q != '\0') {
  90         if (qemu_toupper(*p) != qemu_toupper(*q))
  91             return 0;
  92         p++;
  93         q++;
  94     }
  95     if (ptr)
  96         *ptr = p;
  97     return 1;
  98 }
  99
 100 /* XXX: use host strnlen if available ? */
 101 int qemu_strnlen(const char *s, int max_len)
 102 {
 103     int i;
 104
 105     for(i = 0; i < max_len; i++) {
 106         if (s[i] == '\0') {
 107             break;
 108         }
 109     }
 110     return i;
 111 }
 112
 113 char *qemu_strsep(char **input, const char *delim)
 114 {
 115     char *result = *input;
 116     if (result != NULL) {
 117         char *p;
 118
 119         for (p = result; *p != '\0'; p++) {
 120             if (strchr(delim, *p)) {
 121                 break;
 122             }
 123         }
 124         if (*p == '\0') {
 125             *input = NULL;
 126         } else {
 127             *p = '\0';
 128             *input = p + 1;
 129         }
 130     }
 131     return result;
 132 }
 133
 134 time_t mktimegm(struct tm *tm)
 135 {
 136     time_t t;
 137     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 138     if (m < 3) {
 139         m += 12;
 140         y--;
 141     }
 142     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 143                  y / 400 - 719469);
 144     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 145     return t;
 146 }
 147
 148 /*
 149  * Make sure data goes on disk, but if possible do not bother to
 150  * write out the inode just for timestamp updates.
 151  *
 152  * Unfortunately even in 2009 many operating systems do not support
 153  * fdatasync and have to fall back to fsync.
 154  */
 155 int qemu_fdatasync(int fd)
 156 {
 157 #ifdef CONFIG_FDATASYNC
 158     return fdatasync(fd);
 159 #else
 160     return fsync(fd);
 161 #endif
 162 }
 163
 164 /* vector definitions */
 165 #ifdef __ALTIVEC__
 166 #include <altivec.h>
 167 /* The altivec.h header says we're allowed to undef these for
 168  * C++ compatibility.  Here we don't care about C++, but we
 169  * undef them anyway to avoid namespace pollution.
 170  */
 171 #undef vector
 172 #undef pixel
 173 #undef bool
 174 #define VECTYPE        __vector unsigned char
 175 #define SPLAT(p)       vec_splat(vec_ld(0, p), 0)
 176 #define ALL_EQ(v1, v2) vec_all_eq(v1, v2)
 177 #define VEC_OR(v1, v2) ((v1) | (v2))
 178 /* altivec.h may redefine the bool macro as vector type.
 179  * Reset it to POSIX semantics. */
 180 #define bool _Bool
 181 #elif defined __SSE2__
 182 #include <emmintrin.h>
 183 #define VECTYPE        __m128i
 184 #define SPLAT(p)       _mm_set1_epi8(*(p))
 185 #define ALL_EQ(v1, v2) (_mm_movemask_epi8(_mm_cmpeq_epi8(v1, v2)) == 0xFFFF)
 186 #define VEC_OR(v1, v2) (_mm_or_si128(v1, v2))
 187 #else
 188 #define VECTYPE        unsigned long
 189 #define SPLAT(p)       (*(p) * (~0UL / 255))
 190 #define ALL_EQ(v1, v2) ((v1) == (v2))
 191 #define VEC_OR(v1, v2) ((v1) | (v2))
 192 #endif
 193
 194 #define BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR 8
 195
 196 static bool
 197 can_use_buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 198 {
 199     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 200                    * sizeof(VECTYPE)) == 0
 201             && ((uintptr_t) buf) % sizeof(VECTYPE) == 0);
 202 }
 203
 204 /*
 205  * Searches for an area with non-zero content in a buffer
 206  *
 207  * Attention! The len must be a multiple of
 208  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 209  * and addr must be a multiple of sizeof(VECTYPE) due to
 210  * restriction of optimizations in this function.
 211  *
 212  * can_use_buffer_find_nonzero_offset_inner() can be used to
 213  * check these requirements.
 214  *
 215  * The return value is the offset of the non-zero area rounded
 216  * down to a multiple of sizeof(VECTYPE) for the first
 217  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR chunks and down to
 218  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 219  * afterwards.
 220  *
 221  * If the buffer is all zero the return value is equal to len.
 222  */
 223
 224 static size_t buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 225 {
 226     const VECTYPE *p = buf;
 227     const VECTYPE zero = (VECTYPE){0};
 228     size_t i;
 229
 230     assert(can_use_buffer_find_nonzero_offset_inner(buf, len));
 231
 232     if (!len) {
 233         return 0;
 234     }
 235
 236     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 237         if (!ALL_EQ(p[i], zero)) {
 238             return i * sizeof(VECTYPE);
 239         }
 240     }
 241
 242     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 243          i < len / sizeof(VECTYPE);
 244          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 245         VECTYPE tmp0 = VEC_OR(p[i + 0], p[i + 1]);
 246         VECTYPE tmp1 = VEC_OR(p[i + 2], p[i + 3]);
 247         VECTYPE tmp2 = VEC_OR(p[i + 4], p[i + 5]);
 248         VECTYPE tmp3 = VEC_OR(p[i + 6], p[i + 7]);
 249         VECTYPE tmp01 = VEC_OR(tmp0, tmp1);
 250         VECTYPE tmp23 = VEC_OR(tmp2, tmp3);
 251         if (!ALL_EQ(VEC_OR(tmp01, tmp23), zero)) {
 252             break;
 253         }
 254     }
 255
 256     return i * sizeof(VECTYPE);
 257 }
 258
 259 #if defined CONFIG_AVX2_OPT
 260 #pragma GCC push_options
 261 #pragma GCC target("avx2")
 262 #include <cpuid.h>
 263 #include <immintrin.h>
 264
 265 #define AVX2_VECTYPE        __m256i
 266 #define AVX2_SPLAT(p)       _mm256_set1_epi8(*(p))
 267 #define AVX2_ALL_EQ(v1, v2) \
 268     (_mm256_movemask_epi8(_mm256_cmpeq_epi8(v1, v2)) == 0xFFFFFFFF)
 269 #define AVX2_VEC_OR(v1, v2) (_mm256_or_si256(v1, v2))
 270
 271 static bool
 272 can_use_buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 273 {
 274     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 275                    * sizeof(AVX2_VECTYPE)) == 0
 276             && ((uintptr_t) buf) % sizeof(AVX2_VECTYPE) == 0);
 277 }
 278
 279 static size_t buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 280 {
 281     const AVX2_VECTYPE *p = buf;
 282     const AVX2_VECTYPE zero = (AVX2_VECTYPE){0};
 283     size_t i;
 284
 285     assert(can_use_buffer_find_nonzero_offset_avx2(buf, len));
 286
 287     if (!len) {
 288         return 0;
 289     }
 290
 291     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 292         if (!AVX2_ALL_EQ(p[i], zero)) {
 293             return i * sizeof(AVX2_VECTYPE);
 294         }
 295     }
 296
 297     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 298          i < len / sizeof(AVX2_VECTYPE);
 299          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 300         AVX2_VECTYPE tmp0 = AVX2_VEC_OR(p[i + 0], p[i + 1]);
 301         AVX2_VECTYPE tmp1 = AVX2_VEC_OR(p[i + 2], p[i + 3]);
 302         AVX2_VECTYPE tmp2 = AVX2_VEC_OR(p[i + 4], p[i + 5]);
 303         AVX2_VECTYPE tmp3 = AVX2_VEC_OR(p[i + 6], p[i + 7]);
 304         AVX2_VECTYPE tmp01 = AVX2_VEC_OR(tmp0, tmp1);
 305         AVX2_VECTYPE tmp23 = AVX2_VEC_OR(tmp2, tmp3);
 306         if (!AVX2_ALL_EQ(AVX2_VEC_OR(tmp01, tmp23), zero)) {
 307             break;
 308         }
 309     }
 310
 311     return i * sizeof(AVX2_VECTYPE);
 312 }
 313
 314 static bool avx2_support(void)
 315 {
 316     int a, b, c, d;
 317
 318     if (__get_cpuid_max(0, NULL) < 7) {
 319         return false;
 320     }
 321
 322     __cpuid_count(7, 0, a, b, c, d);
 323
 324     return b & bit_AVX2;
 325 }
 326
 327 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
 328          __attribute__ ((ifunc("can_use_buffer_find_nonzero_offset_ifunc")));
 329 size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
 330          __attribute__ ((ifunc("buffer_find_nonzero_offset_ifunc")));
 331
 332 static void *buffer_find_nonzero_offset_ifunc(void)
 333 {
 334     typeof(buffer_find_nonzero_offset) *func = (avx2_support()) ?
 335         buffer_find_nonzero_offset_avx2 : buffer_find_nonzero_offset_inner;
 336
 337     return func;
 338 }
 339
 340 static void *can_use_buffer_find_nonzero_offset_ifunc(void)
 341 {
 342     typeof(can_use_buffer_find_nonzero_offset) *func = (avx2_support()) ?
 343         can_use_buffer_find_nonzero_offset_avx2 :
 344         can_use_buffer_find_nonzero_offset_inner;
 345
 346     return func;
 347 }
 348 #pragma GCC pop_options
 349 #else
 350 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
 351 {
 352     return can_use_buffer_find_nonzero_offset_inner(buf, len);
 353 }
 354
 355 size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 356 {
 357     return buffer_find_nonzero_offset_inner(buf, len);
 358 }
 359 #endif
 360
 361 /*
 362  * Checks if a buffer is all zeroes
 363  *
 364  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 365  * restriction of optimizations in this function.
 366  */
 367 bool buffer_is_zero(const void *buf, size_t len)
 368 {
 369     /*
 370      * Use long as the biggest available internal data type that fits into the
 371      * CPU register and unroll the loop to smooth out the effect of memory
 372      * latency.
 373      */
 374
 375     size_t i;
 376     long d0, d1, d2, d3;
 377     const long * const data = buf;
 378
 379     /* use vector optimized zero check if possible */
 380     if (can_use_buffer_find_nonzero_offset(buf, len)) {
 381         return buffer_find_nonzero_offset(buf, len) == len;
 382     }
 383
 384     assert(len % (4 * sizeof(long)) == 0);
 385     len /= sizeof(long);
 386
 387     for (i = 0; i < len; i += 4) {
 388         d0 = data[i + 0];
 389         d1 = data[i + 1];
 390         d2 = data[i + 2];
 391         d3 = data[i + 3];
 392
 393         if (d0 || d1 || d2 || d3) {
 394             return false;
 395         }
 396     }
 397
 398     return true;
 399 }
 400
 401 #ifndef _WIN32
 402 /* Sets a specific flag */
 403 int fcntl_setfl(int fd, int flag)
 404 {
 405     int flags;
 406
 407     flags = fcntl(fd, F_GETFL);
 408     if (flags == -1)
 409         return -errno;
 410
 411     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 412         return -errno;
 413
 414     return 0;
 415 }
 416 #endif
 417
 418 static int64_t suffix_mul(char suffix, int64_t unit)
 419 {
 420     switch (qemu_toupper(suffix)) {
 421     case QEMU_STRTOSZ_DEFSUFFIX_B:
 422         return 1;
 423     case QEMU_STRTOSZ_DEFSUFFIX_KB:
 424         return unit;
 425     case QEMU_STRTOSZ_DEFSUFFIX_MB:
 426         return unit * unit;
 427     case QEMU_STRTOSZ_DEFSUFFIX_GB:
 428         return unit * unit * unit;
 429     case QEMU_STRTOSZ_DEFSUFFIX_TB:
 430         return unit * unit * unit * unit;
 431     case QEMU_STRTOSZ_DEFSUFFIX_PB:
 432         return unit * unit * unit * unit * unit;
 433     case QEMU_STRTOSZ_DEFSUFFIX_EB:
 434         return unit * unit * unit * unit * unit * unit;
 435     }
 436     return -1;
 437 }
 438
 439 /*
 440  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 441  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 442  * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
 443  * other error.
 444  */
 445 int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
 446                             const char default_suffix, int64_t unit)
 447 {
 448     int64_t retval = -EINVAL;
 449     char *endptr;
 450     unsigned char c;
 451     int mul_required = 0;
 452     double val, mul, integral, fraction;
 453
 454     errno = 0;
 455     val = strtod(nptr, &endptr);
 456     if (isnan(val) || endptr == nptr || errno != 0) {
 457         goto fail;
 458     }
 459     fraction = modf(val, &integral);
 460     if (fraction != 0) {
 461         mul_required = 1;
 462     }
 463     c = *endptr;
 464     mul = suffix_mul(c, unit);
 465     if (mul >= 0) {
 466         endptr++;
 467     } else {
 468         mul = suffix_mul(default_suffix, unit);
 469         assert(mul >= 0);
 470     }
 471     if (mul == 1 && mul_required) {
 472         goto fail;
 473     }
 474     if ((val * mul >= INT64_MAX) || val < 0) {
 475         retval = -ERANGE;
 476         goto fail;
 477     }
 478     retval = val * mul;
 479
 480 fail:
 481     if (end) {
 482         *end = endptr;
 483     }
 484
 485     return retval;
 486 }
 487
 488 int64_t qemu_strtosz_suffix(const char *nptr, char **end,
 489                             const char default_suffix)
 490 {
 491     return qemu_strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 492 }
 493
 494 int64_t qemu_strtosz(const char *nptr, char **end)
 495 {
 496     return qemu_strtosz_suffix(nptr, end, QEMU_STRTOSZ_DEFSUFFIX_MB);
 497 }
 498
 499 /**
 500  * Helper function for qemu_strto*l() functions.
 501  */
 502 static int check_strtox_error(const char *p, char *endptr, const char **next,
 503                               int err)
 504 {
 505     /* If no conversion was performed, prefer BSD behavior over glibc
 506      * behavior.
 507      */
 508     if (err == 0 && endptr == p) {
 509         err = EINVAL;
 510     }
 511     if (!next && *endptr) {
 512         return -EINVAL;
 513     }
 514     if (next) {
 515         *next = endptr;
 516     }
 517     return -err;
 518 }
 519
 520 /**
 521  * QEMU wrappers for strtol(), strtoll(), strtoul(), strotull() C functions.
 522  *
 523  * Convert ASCII string @nptr to a long integer value
 524  * from the given @base. Parameters @nptr, @endptr, @base
 525  * follows same semantics as strtol() C function.
 526  *
 527  * Unlike from strtol() function, if @endptr is not NULL, this
 528  * function will return -EINVAL whenever it cannot fully convert
 529  * the string in @nptr with given @base to a long. This function returns
 530  * the result of the conversion only through the @result parameter.
 531  *
 532  * If NULL is passed in @endptr, then the whole string in @ntpr
 533  * is a number otherwise it returns -EINVAL.
 534  *
 535  * RETURN VALUE
 536  * Unlike from strtol() function, this wrapper returns either
 537  * -EINVAL or the errno set by strtol() function (e.g -ERANGE).
 538  * If the conversion overflows, -ERANGE is returned, and @result
 539  * is set to the max value of the desired type
 540  * (e.g. LONG_MAX, LLONG_MAX, ULONG_MAX, ULLONG_MAX). If the case
 541  * of underflow, -ERANGE is returned, and @result is set to the min
 542  * value of the desired type. For strtol(), strtoll(), @result is set to
 543  * LONG_MIN, LLONG_MIN, respectively, and for strtoul(), strtoull() it
 544  * is set to 0.
 545  */
 546 int qemu_strtol(const char *nptr, const char **endptr, int base,
 547                 long *result)
 548 {
 549     char *p;
 550     int err = 0;
 551     if (!nptr) {
 552         if (endptr) {
 553             *endptr = nptr;
 554         }
 555         err = -EINVAL;
 556     } else {
 557         errno = 0;
 558         *result = strtol(nptr, &p, base);
 559         err = check_strtox_error(nptr, p, endptr, errno);
 560     }
 561     return err;
 562 }
 563
 564 /**
 565  * Converts ASCII string to an unsigned long integer.
 566  *
 567  * If string contains a negative number, value will be converted to
 568  * the unsigned representation of the signed value, unless the original
 569  * (nonnegated) value would overflow, in this case, it will set @result
 570  * to ULONG_MAX, and return ERANGE.
 571  *
 572  * The same behavior holds, for qemu_strtoull() but sets @result to
 573  * ULLONG_MAX instead of ULONG_MAX.
 574  *
 575  * See qemu_strtol() documentation for more info.
 576  */
 577 int qemu_strtoul(const char *nptr, const char **endptr, int base,
 578                  unsigned long *result)
 579 {
 580     char *p;
 581     int err = 0;
 582     if (!nptr) {
 583         if (endptr) {
 584             *endptr = nptr;
 585         }
 586         err = -EINVAL;
 587     } else {
 588         errno = 0;
 589         *result = strtoul(nptr, &p, base);
 590         /* Windows returns 1 for negative out-of-range values.  */
 591         if (errno == ERANGE) {
 592             *result = -1;
 593         }
 594         err = check_strtox_error(nptr, p, endptr, errno);
 595     }
 596     return err;
 597 }
 598
 599 /**
 600  * Converts ASCII string to a long long integer.
 601  *
 602  * See qemu_strtol() documentation for more info.
 603  */
 604 int qemu_strtoll(const char *nptr, const char **endptr, int base,
 605                  int64_t *result)
 606 {
 607     char *p;
 608     int err = 0;
 609     if (!nptr) {
 610         if (endptr) {
 611             *endptr = nptr;
 612         }
 613         err = -EINVAL;
 614     } else {
 615         errno = 0;
 616         *result = strtoll(nptr, &p, base);
 617         err = check_strtox_error(nptr, p, endptr, errno);
 618     }
 619     return err;
 620 }
 621
 622 /**
 623  * Converts ASCII string to an unsigned long long integer.
 624  *
 625  * See qemu_strtol() documentation for more info.
 626  */
 627 int qemu_strtoull(const char *nptr, const char **endptr, int base,
 628                   uint64_t *result)
 629 {
 630     char *p;
 631     int err = 0;
 632     if (!nptr) {
 633         if (endptr) {
 634             *endptr = nptr;
 635         }
 636         err = -EINVAL;
 637     } else {
 638         errno = 0;
 639         *result = strtoull(nptr, &p, base);
 640         /* Windows returns 1 for negative out-of-range values.  */
 641         if (errno == ERANGE) {
 642             *result = -1;
 643         }
 644         err = check_strtox_error(nptr, p, endptr, errno);
 645     }
 646     return err;
 647 }
 648
 649 /**
 650  * parse_uint:
 651  *
 652  * @s: String to parse
 653  * @value: Destination for parsed integer value
 654  * @endptr: Destination for pointer to first character not consumed
 655  * @base: integer base, between 2 and 36 inclusive, or 0
 656  *
 657  * Parse unsigned integer
 658  *
 659  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 660  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 661  *
 662  * If @s is null, or @base is invalid, or @s doesn't start with an
 663  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 664  * return -EINVAL.
 665  *
 666  * Set *@endptr to point right beyond the parsed integer (even if the integer
 667  * overflows or is negative, all digits will be parsed and *@endptr will
 668  * point right beyond them).
 669  *
 670  * If the integer is negative, set *@value to 0, and return -ERANGE.
 671  *
 672  * If the integer overflows unsigned long long, set *@value to
 673  * ULLONG_MAX, and return -ERANGE.
 674  *
 675  * Else, set *@value to the parsed integer, and return 0.
 676  */
 677 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 678                int base)
 679 {
 680     int r = 0;
 681     char *endp = (char *)s;
 682     unsigned long long val = 0;
 683
 684     if (!s) {
 685         r = -EINVAL;
 686         goto out;
 687     }
 688
 689     errno = 0;
 690     val = strtoull(s, &endp, base);
 691     if (errno) {
 692         r = -errno;
 693         goto out;
 694     }
 695
 696     if (endp == s) {
 697         r = -EINVAL;
 698         goto out;
 699     }
 700
 701     /* make sure we reject negative numbers: */
 702     while (isspace((unsigned char)*s)) {
 703         s++;
 704     }
 705     if (*s == '-') {
 706         val = 0;
 707         r = -ERANGE;
 708         goto out;
 709     }
 710
 711 out:
 712     *value = val;
 713     *endptr = endp;
 714     return r;
 715 }
 716
 717 /**
 718  * parse_uint_full:
 719  *
 720  * @s: String to parse
 721  * @value: Destination for parsed integer value
 722  * @base: integer base, between 2 and 36 inclusive, or 0
 723  *
 724  * Parse unsigned integer from entire string
 725  *
 726  * Have the same behavior of parse_uint(), but with an additional check
 727  * for additional data after the parsed number. If extra characters are present
 728  * after the parsed number, the function will return -EINVAL, and *@v will
 729  * be set to 0.
 730  */
 731 int parse_uint_full(const char *s, unsigned long long *value, int base)
 732 {
 733     char *endp;
 734     int r;
 735
 736     r = parse_uint(s, value, &endp, base);
 737     if (r < 0) {
 738         return r;
 739     }
 740     if (*endp) {
 741         *value = 0;
 742         return -EINVAL;
 743     }
 744
 745     return 0;
 746 }
 747
 748 int qemu_parse_fd(const char *param)
 749 {
 750     long fd;
 751     char *endptr;
 752
 753     errno = 0;
 754     fd = strtol(param, &endptr, 10);
 755     if (param == endptr /* no conversion performed */                    ||
 756         errno != 0      /* not representable as long; possibly others */ ||
 757         *endptr != '\0' /* final string not empty */                     ||
 758         fd < 0          /* invalid as file descriptor */                 ||
 759         fd > INT_MAX    /* not representable as int */) {
 760         return -1;
 761     }
 762     return fd;
 763 }
 764
 765 /*
 766  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 767  * Input is limited to 14-bit numbers
 768  */
 769 int uleb128_encode_small(uint8_t *out, uint32_t n)
 770 {
 771     g_assert(n <= 0x3fff);
 772     if (n < 0x80) {
 773         *out++ = n;
 774         return 1;
 775     } else {
 776         *out++ = (n & 0x7f) | 0x80;
 777         *out++ = n >> 7;
 778         return 2;
 779     }
 780 }
 781
 782 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 783 {
 784     if (!(*in & 0x80)) {
 785         *n = *in++;
 786         return 1;
 787     } else {
 788         *n = *in++ & 0x7f;
 789         /* we exceed 14 bit number */
 790         if (*in & 0x80) {
 791             return -1;
 792         }
 793         *n |= *in++ << 7;
 794         return 2;
 795     }
 796 }
 797
 798 /*
 799  * helper to parse debug environment variables
 800  */
 801 int parse_debug_env(const char *name, int max, int initial)
 802 {
 803     char *debug_env = getenv(name);
 804     char *inv = NULL;
 805     long debug;
 806
 807     if (!debug_env) {
 808         return initial;
 809     }
 810     errno = 0;
 811     debug = strtol(debug_env, &inv, 10);
 812     if (inv == debug_env) {
 813         return initial;
 814     }
 815     if (debug < 0 || debug > max || errno != 0) {
 816         fprintf(stderr, "warning: %s not in [0, %d]", name, max);
 817         return initial;
 818     }
 819     return debug;
 820 }
 821
 822 /*
 823  * Helper to print ethernet mac address
 824  */
 825 const char *qemu_ether_ntoa(const MACAddr *mac)
 826 {
 827     static char ret[18];
 828
 829     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 830              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 831
 832     return ret;
 833 }